xxi THE CHURCH OF S. MARY OF THE MONGOLS 277 Sultan Mehemed the efforts to expropriate the building were frustrated.1 Among the Turks the building is known as Kan KIlisses the church of Blood, and the adjoining street goes by the name Sanjakdar Youkousou, the ascent of the standard-bearer/ terms which refer to the desperate struggle between Greeks and Turks at this point on the morning of the capture of the city,3 Architectural Features Although the building has always been in Christian hands it has suffered alterations almost more drastic than any undergone by churches converted into mosques. The interior has been stripped of its original decoration, and is so blocked by eikons, chandeliers, and other ornaments as to render a proper examination of the church extremely difficult. In plan the church is a domed quatrefoil building, the only example of that type found In Constantinople, The central dome rests on a cross formed by four semi-domes, which are 'further enlarged below the vaulting level by three large semicircular niches. It is placed on a drum of eight concave compartments pierced by windows to the outside circular and crowned with a flat cornice. Externally the semi-domes and apse are five-sided. From the interior face of the apse and on its northern wall projects a capital, adorned with acanthus leaves, which, as it could never have stood free in this position, probably formed part of an eikonostasis In stone. The narthex is In three bays, the central bay being covered by a barrel vault, while the lateral bays have low drumless domes on pen-dentives. The entrance is by a door In the central bay, and from that bay the church Is entered through a passage cut in the central niche of the western semi-dome, and slightly wider than the niche. The end bays open, respectively, into the northern and southern semi-domes 1 Patr. Constantius, pp. 84-86, The Greek community retains also other churches founded before the Turkish conquest, but they are wholly modern buildings, 2 Ibid. pp. 85-86. 3 N. Barbaro, p. 818.